title: Electron microscopic and cytochemical observations of theophylline and melanocyte-stimulating hormone effects on melanoma cells in culture.
abstract: The effects of theophylline and melanocyte-stimulating hormone on B16 melanoma cells in culture cells were studied by electron microscopy and dopa cytochemistry. The data show that theophylline and melanocyte-stimulating hormone enhance melanogenesis by activating tyrosinase synthesis and its transfer but that neither affects the synthesis of the well-organized eumelanosome matrix. Their pigmenting effects appear to be limited to the melanogenic cells and result from a marked increase, particularly in theophylline-treated cells, in pheomelanosome formation.
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D008545:Melanoma / Q000378:metabolism / Q000648:ultrastructure*; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000648:ultrastructure; D013806:Theophylline / Q000494:pharmacology*
chemical_list: D004295:Dihydroxyphenylalanine; D009074:Melanocyte-Stimulating Hormones; D013806:Theophylline